On conventional steel white bodies the side sill is formed of outer and inner panels that are welded together and is secured to the surrounding body construction. Stiffeners and reinforcements can be added inside of the side sill for crash specific strength. The side sills are typically made of high strength steel for crash. Aluminum vehicle frames typically apply an extruded section for the side sill, and reinforcements can be added to the extrusion to provide additional strength for performance. The side sill is a critical part for pole impacts and must have sufficient crush and energy absorption to prevent intrusion to the passenger cabin. The side sill also needs to have sufficient torsion performance for structural rigidity of the vehicle and axial crush for front impacts. And because the side sill is the largest part on the vehicle the cross sectional area of the section needs to be reduced as much as possible.